[RESOLVED] [VB6] - using SendMessage() with no event arguments(like Paint)

[joaquim]

i'm trying using the SendMessage() api function for call the Paint event:

Private PrevWin2 As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal HWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal HWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal HWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Const GWL_WNDPROC = (-4)
Private Const WM_PAINT = &HF

Private Function Proc2(ByVal HWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    
    ' Pass mouse wheel as arrow keys to a window handle(user controls).
    If IsCodeWindowActivated = False Then
        SendMessage HWnd, WM_PAINT, vbNull, vbNull
        Unhook2 HWnd
    End If
    Proc2 = CallWindowProc(PrevWin2, HWnd, Msg, wParam, lParam)
End Function

Public Sub Hook2(Handle As Long)
    If PrevWin2 = 0 Then
        PrevWin2 = SetWindowLong(Handle, GWL_WNDPROC, AddressOf Proc2)
    End If
End Sub

Public Sub Unhook2(Handle As Long)
    If PrevWin2 Then
        Call SetWindowLong(Handle, GWL_WNDPROC, PrevWin2)
        PrevWin2 = 0
    End If
End Sub

when i use the SendMessage() the VB6 program is closed
i belive that my problem is here:

SendMessage HWnd, WM_PAINT, vbNull, vbNull

how can i use the SendMessage() without arguments event?
(like Paint event, because don't have arguments)
(what i need is call the Paint event)

[LaVolpe]

If you read the MSDN documentation on WM_Paint, you will see you should not call it directly unless you are trying to have the target draw to a DC passed in the wParam parameter.

To force a window to repaint, consider one of these APIs: UpdateWindow or RedrawWindow

P.S. vbNull = 1, not zero. You are telling the destination to paint to a DC value of 1; could be reason for lock/crash.

SendMessage HWnd, WM_PAINT, 0&, ByVal 0&

[joaquim]

If you read the MSDN documentation on WM_Paint, you will see you should not call it directly unless you are trying to have the target draw to a DC passed in the wParam parameter.

To force a window to repaint, consider one of these APIs: UpdateWindow or RedrawWindow

P.S. vbNull = 1, not zero. You are telling the destination to paint to a DC value of 1; could be reason for lock/crash.

SendMessage HWnd, WM_PAINT, 0&, ByVal 0&

sorry not working. i just need call the Paint or Show event(because they activate the timer)

[joaquim]

yes... thanks

RedrawWindow hwnd, ByVal 0&, ByVal 0&, RDW_INVALIDATE

instead SendMessage() i use that function. thanks for everything